The invention relates to facilities cast into concrete structures, and more particularly to pulling irons or hooks for such structures.
Lifting hooks or pulling irons are facilities embedded in concrete structures. They are engaged by devices that require a solid mount to generate tension. Such devices may include tensioners used to pull wires and cables, or lifting apparatus such as the hook of a crane""s cable used to support a structure for installation. One such structure is a concrete utility vault, which is an open-topped box that is placed in an excavation, and which has apertures in the side walls to receive utility lines. Several pulling irons are normally embedded in the interior wall surfaces, so that wire pulling devices may be used to pull utility lines.
To facilitate construction, especially casting of the structures, the pulling irons are recessed within the volume of the wall, and do not protrude beyond the plane of the wall. The hooks are kept accessible by the use of pocket elements that are essentially bowls whose rims are positioned at the wall surface where the hook is to be accessed. The hook is an articulated bar, such as of rigid cable, with an inverted V-shaped loop portion that has a vertex extending into the bowl""s cavity, and with legs of the V and laterally extending end portions embedded in the concrete, attached to reinforcing bars within the structure.
While functional, this configuration has several disadvantages. The bar""s loop extends through a slot in the bowl. Prior to the structure being cast, the bar must be held in the desired position, and the bowl must be maintained with its rim against the surface of the form that will define the resulting wall surface. To prevent the bowl from pivoting and becoming misaligned during pouring of the concrete, the bowl and bar must be secured to each other. In existing designs, this is typically achieved by strapping the two elements together with duct tape, a time consuming and imprecise process. Moreover, even if the two are secured to each other to prevent concrete incursion into the bowl cavity, some angular misalignment may still result even when the bowl is flush to the form surface. This can occur when the bar ends are displaced, causing the bar loop to be closer of farther from the wall than is desired.
The embodiment disclosed herein overcomes these disadvantages by providing a pulling iron facility for encapsulation in a concrete structure. The facility has an elongated strength member with an intermediate portion forming an upwardly extending loop. The strength member has opposed end portions extending laterally away from the loop. A sleeve at least in part encapsulates the strength member, and includes a planar flange below at least a portion of the loop and defining an enclosed loop aperture. The sleeve includes a number of protrusions spaced apart from the flange.